This PR was merged into the 5.2-dev branch.

Discussion
----------

[Notifier] Add Zulip notifier bridge

| Q             | A
| ------------- | ---
| Branch?       | master
| Bug fix?      | no
| New feature?  | yes
| Deprecations? | no
| Tickets       | See #33687
| License       | MIT
| Doc PR        | symfony/symfony-docs#13604

This adds a [Zulip](https://zulipchat.com/) (another popular open source Slack alternative) transport for the new Notifier component.

#### Sample DSN

```ZULIP_DSN=zulip://test-bot@zulipchat.com:api-key@example.zulipchat.com?channel=builds```

#### Configuration

```yml
# config/packages/notifier.yaml
framework:
    notifier:
        chatter_transports:
            zulip: '%env(ZULIP_DSN)%'
```

#### Example

```php
public function index(ChatterInterface $chatter)
{
    $message = (new ChatMessage('New order arrived!', new ZulipOptions('Ordering')))
        ->transport('zulip');

    $chatter->send($message);

    ...
}
```

Commits
-------

bd4fd32 Adds Zulip notifier bridge